Multi-needle quilting machines are used in the commercial manufacture of large size quilted products such as mattress covers and comforters. One such machine is described in U.S. Pat. No. 5,154,130, hereby expressly incorporated herein by reference. These machines include multiple needle arrays that reciprocate each of a plurality of needles simultaneously through a multiple layered quilted fabric, typically in a motion that is sinusoidal as function of time, to sew a separate series of chain stitches with each needle. The needles cooperate with a plurality of loopers or hooks in a corresponding array on the opposite side of the fabric from the needles to form double lock chain stitches in each of the series. The loopers are similarly driven simultaneously in an oscillating angular motion about an axis that is also usually a sinusoidal function of time. In addition to the motions of the needles and loopers, there is the motion of a presser foot plate or plates situated on the same side of the fabric as the needles that reciprocate to compress the multiple layered fabric in synchronization with the needle motion to facilitate the sewing.
Usually, the motion of the needles, the motion of the loopers, and the motion of the presser foot plate or plates are driven by a common drive motor through a common rotary drive shaft that extends transversely across the machine. Typically, the needles and loopers have been driven by separate eccentrics located on the drive shaft, with the presser foot plates driven by linkage from the eccentric that drives the needles. The separate eccentric drives have been provided because the needle assemblies and looper assemblies have been treated as different motions that should be separately adjusted during manufacture and maintenance. The separate drives also distribute the different loads of the various assemblies.
More recently, a third eccentric drive has been deemed desirable for machines of the prior art for separately driving the pressure foot assembly. One such drive is disclosed in U.S. Pat. No. 7,735,439.
While the separate eccentric drive systems have been regarded as serving engineering purposes in the prior art, they are associated with certain levels of vibration, maintenance, and manufacturing costs, the reduction of which would be desirable to machine manufacturers and owners. Such separate systems also have the ability to lose synchronization, making maintenance important to avoid machine malfunction and damage.